The letter, written to participants of the inquiry, says: "The chairman will be in a position to write to the prime minister with his final report after the parliamentary recess, for publication most likely in October."

According to the letter, the second phase is still due to go ahead in January 2020.

Image copyrightGetty ImagesImage caption
The families of the 72 victims contributed to the report

Natasha Elcock, chairwoman of Grenfell United, the group for survivors and bereaved families, said it was disgraceful that the inquiry had "underestimated the complexity of the evidence" that was produced in the first phase.

She said: "That we are only finding this out now, when we were expecting the report to be published ahead of the two-year anniversary, shows how they continue to disregard survivors and bereaved through this process."

Elizabeth Campbell, leader of Kensington and Chelsea Council, said the news will be "very disappointing" to the families and the communities in the borough.

She said: "We all want to get to the truth of what happened nearly two years ago, and we hope the inquiry can still move forward despite the delay to this report.

"I want to reiterate that our approach to the inquiry has been to provide the witnesses they have asked for and the documents they require. We are serious about our role in making sure a tragedy like this never happens again."

The news comes as some from the Grenfell community said they wanted an independent panel to be put in place before hearings resume next year.

They also called for a venue layout for the inquiry that puts families at the centre of proceedings, and for the government to help workers attend the inquiry without losing their annual leave.